Grating structure

ABSTRACT

A grating structure having a plurality of regularly staggered parallelly disposed elliptically-shaped openings defining substantially uninterrupted ribs therebetween increasing the structural strength and load bearing capabilities of the grating structure. A plurality of perforated traction nubs are disposed in a single file along the ribs to define center lines along which cuts, bends, etc. are suitably made without producing jagged peripheral edges requiring end caps or the like and preventing slippage on the grating structure. Individual dishshaped clamp means nest within certain of the elliptically-shaped openings for joining the same with other structural members.

United States Patent lnventor Robert J. Evans Aurora, 111. Appl. No. 780,780 Filed Dec. 3, 1968 Patented Feb. 23, 1971 Assignee Aurora Equipment Compiny Aurora, Ill.

GRATING STRUCTURE 16 Claims, 12 Drawing Figs. 11.8. C1 182/ 106, 182/194, 52/633 Int. Cl. E060 7/18, E060 1/38 Field of Search 182/228, 106, 194; 52/182, 633, 80; 94/5 References Cited UNITED STATES PATENTS 2,278,554 4/ 1942 Morton 94/5 3,127,961 4/1964 Frazier 52/633 3,093,216 6/1963 Dunham 94/5 3,181,440 5/1965 Mullaney.... 94/5 3,307,653 3/1967 Gnehm 182/106 Primary Examiner-Reinaldo P. Machado Att0rney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: A grating structure having a plurality of regularly staggered parallelly disposed elliptically-shaped openings defining substantially uninterrupted ribs therebetween increasing the structural strength and load bearing capabilities of the grating structure. A plurality of perforated traction nubs are disposed in a single file along the ribs to define center lines along which cuts, bends, etc. are suitably made without producing jagged peripheral edges requiring end caps or the like and preventing slippage on the grating structure. Individual dish-shaped clamp means nest within certain of the elliptically-shaped openings for joining the same with other structural members.

PATENTE-U E82 31% SHEET 2 0F 3 I 5 I F GRATING STRUCTURE The invention relates to steel structural members and more particularly to grating structural members for use as stair treads, catwalk decking, floor decking, etc.

Various types of grating structures are known having square, round, diamond-shaped, etc. openings in various configurations. The known open grating structures have one or more drawbacks including lack of overall strength (in comparison with integral solid-type of grating structures), inconvenient spacing of the openings resulting in jagged peripheral edges when straight-lined cuts or bends are made on such structures, insufficient strength to weight ratios, unsatisfactory means of fastening such grating structures to other structures, etc. The grating structure of the present invention is provided with unique deep drawn elliptical openings spaced in a novel configuration whereby added overall strength, greater strength to weight ratio, spacing allowing formation of smooth nonjagged edges along cuts or bends and an improved means of fastening such novel grid structures to other structures is provided. j

Accordingly, it is an important object of the invention to provide an improved grid structure overcoming the aforesaid drawbacks.

It is a further object of the invention to provide a novel grid structure having a plurality of regularly staggered parallelly disposed elliptically-shaped openings. defining substantial uninterrupted ribs therebetween.

It is yet a further object of the instant invention to provide a unique configuration of openings in a grating structure allowing formation of smooth nonjagged' ends along straight-lined cuts or bends on such grating structures.

Yet a further object of the invention is to provide a new and improved grating structure for use in catwalks, stair treads and the like having ribs of substantially uninterrupted material having perforated traction nubs thereon resistant to slippage.

A feature of the invention relates to the manufacture of a new and improved grating structure having a plurality of regularly staggered parallelly disposed elliptically-shaped openings defining substantially uninterrupted ribs therebetween increasing the structural strength and load bearing capabilities of the grating structure and a plurality of perforated traction nubs disposed on the ribs to resist slippage on the grating structure with individual dished clamp means nesting within certain of the openings for retaining bolts or the like in fastening the grid structure to other structural members.

Other objects, features and advantages of the present invention will become more fully apparent in view of the following detailed description of the preferred embodiments of the invention in the specification, claims and drawings in which:

FIG. 1 is an elevational schematic view, with parts broken away, illustrating a staircase constructed with an improved grating structure in accordance with the principles of the invention;

FIG. 2 is an enlarged detailed view taken substantially along circled portion II-ll of FIG. 1 showing features of the supporting structure;

FIG. 3 is a planlike view, with parts broken away, illustrating a portion of one embodiment of the grid structure con structed in accordance with the principles of the invention;

FIG. 4 is a side elevational view of a grid structure of the invention taken substantially along line lV-IV of FIG. 3;

FIG. 5 is a partial plan view illustrating another embodiment of the grid structure constructed in accordance with the prin ciples of the invention;

FIG. 6 is an elevated sectional view taken substantially along lines Vl-VI of FIG. 5 showing additional details thereof;

FIG. 7 is a somewhat elevated perspective view of a preferred form of the clamp means utilized with the gratin structure of the invention;

FIG. 3 is an elevated sectional view taken substantially along lines VIII-VIII of FIG. 1;

FIG. 9 is an elevated sectional view taken substantially along lines IX-IX of FIG. 1;

FIG. 10 is an elevational schematic view illustrating a preferred embodiment of a staircase constructed in accordance with the principles of the invention;

FIG. 11 is an enlarged elevational view of a portion of the staircase illustrated in FIG. 10; and

FIG. 12 is an exploded elevational view of a portion of a preferred handrail construction utilized in accordance with the principles of the invention.

AS SHOWN ON THE DRAWINGS The reference numeral 10 in FIG. 1 generally indicates a staircase utilizing the grid structure ll of the invention constructed in accordance with the principles of the invention. The staircase 10 is provided with upright end support means 12 and 13 and a centralized upright'support means 14 suitably fastened by cleat means C to a base floor or support F. A stringer member 15 is suitably attached, as by bolt means to support means 12, 13 and 14 in an angular relationship to define the pitch of the stairs. A handrail member 16 is suitably attached, as by bolt means 19, in a capping relationship (although an adjacent relationship could also be utilized) with support means l2, l3 and 14 in a substantially parallel relationship to stringer member 15 to provide hand support for one using the stairs. As will be appreciated, substantially similar support means, stringer member and handrail member (if desired) may also be provided on the opposing side of the structure shown to complete the staircase.

Stringer member 15 has a plurality of tread support membars 17 suitably attached thereto, as by bolting or welding, supporting individual stair treads 1]. It will be noted that support members 17 are adapted, in this instance, to support the stair treads 11 below the stringer member. Stair treads 11 comprise the grid structure of the invention, the details of which will be explained in greater detail hereinafter.

FIG. 2 illustrates further details of the connection between the upright support member 13 and the handrail member 16. As will be appreciated, all of the upright support members l2, l3 and 14 may be of substantially similar construction. In addition, stringer member 15 may likewise be of similar construction as upright support members 12, 13 and 14. As best seen in FIG. 9, upright member 13 is preferably composed of two L-shaped elements, each having perpendicularly disposed flanges 1311,1311, and 13a, 13b. The flanges 13a and 13a are suitably fastened in an overlapping relationship to define a channel-sectioned upright support member 13. Flanges 13a, 13a are provided with a plurality of generally parallely aligned rows of openings. Openings 13d are somewhat longitudinally elongated and disposed near the longitudinal edges of flanges 13a, 13a and these openings comprise the outer rows of openings. The inner row of openings is composed of openings Be and 13f in alternating relationship to each other and substantially aligned along the centerline of flanges 13a, 13a. Openings 13f are somewhat transversely elongated while openings 13e are generally circular in shape. The overlapping relationship of the L-shaped members 13a, 13b, 13a, 13b provide added structural strength to the upright support member 13 along its major stress axis, while side flanges 13b, 13b provide added rigidity to the support member. As will be appreciated, a single construction channel-member may also be utilized as a support member, however, the L-shpaed elements described are substantially more convenient to handle and are more economical.

Handrail member 16 is also preferably constructed of a similar pair of L-shaped elements having flanges 16a, 16b, 16a, 16b, as best seen in FIG. 8. It should be pointed out that flanges 16b, 16b of'handrail 16 are wider (approximately by the thickness of the metal comprising these elements) than flanges 13b, 13b. This relationship allows the handrail to fit over the top of the upright support members l2, l3 and I4. Flanges 16a, 16a of handrail 16 are provided with a plurality of generally parallelly aligned rows of openings. The row disposed next to flanges 16a, 1611' has substantially longitudinally elongated slot-shape openings 16d. The row disposed next to the outer edge of flanges 16b, 16b has somewhat elongated oblong-shaped openings Me. The row between the aforesaid rows has openings 16f and 16g in alternating relationship along the substantial centerline of the flange. Openings 16f are somewhat transversely elongated while openings 16g are somewhat circular in shape.

As will be noted from FIG. 2, flanges 13a of upright support member 13 directly contact flange 16b of handrail 16 to provide a cap means on the upright support member 13. The opening 16c is suitably aligned with opening 132 to allow fastening bolt 19 to pass therethrough and rigidly join the handrail member 16 to the upright member 13. As has been previously indicated, similar joints are made between the handrail and the upright members 12 and 14. Of course, stringer member 15 is suitably similarly joined with upright members 12, 13 and 14, i.e., holes in the back or body portion thereof are aligned with holes in the upright members and bolts pass therethrough. Attention is also directed to FIG. 12, which illustrates an additional feature of the handrail to be discussed hereinafter.

Referring now to FIG. 3, wherein a stair tread 11 comprising the grid structure of the invention is illustrated. The grid structure 11 may be utilized as a stair tread, catwalk decking, floor decking, walkway decking, pit covering, etc. and is constructed of a one-piece sheet metal panel of any desired gauge, but preferably 13 gauge. The one-piece sheet metal panel is preferably provided with a main panel portion 21 with its opposed longitudinal margins 26 turned under and providing support flange 24 underlying the main panel portions and thereby defining a channel cross section (however, a panel having only a main panel portion and marginal means for fastening to other structures may be utilized). The support flanges or turned under longitudinal margin 24 may be provided with slots 24a at their respective ends for receiving anchoring means 25 securing the grating structure 11 to other structural elements. The main panel portion 21 of the grid structure 11 is provided with a plurality of regularly spaced transversely staggered longitudinally-parallel substantially elliptically-shaped openings 22 defining substantially uninterrupted ribs 21b therebetween increasing the structural strength of the main panel and increasing its load bearing capabilities. The substantially uninterrupted ribs 21b carry a plurality of traction nubs 23 in a substantial straight line alignment with said ribs to provide slippage-resistant areas on the main panel 21, which are preferably perforated and frustoconical in cross section. The frustoconical perforation traction nubs 23 are relatively small and function to further strengthen the rib areas 21b. Further, the frustoconical traction nubs have inclined surfaces intersecting at an edge positioned above the main panel portion 21 to further augment the slippage resistant characteristics thereof. The ellipticallyshaped openings 22 have relatively deep-drawn peripheral boundaries and thus provide additional strength to the main panel portion 21 and define reinforced ribs or rib areas 21b. It will be noted that bends or cuts may be made substantially along the line tangent of the perforated traction nubs 23 without producing jagged nonsmooth edges. Of course, smooth edges of this type do not require end caps or the like.

Referring now to FIG. 4, wherein a schematic elevational view of grid structure 11 is illustrated, the grid structure 11 is provided with a main panel 21 having opposed substantially perpendicular spacing flanges 26 connected to underlying support flanges 24. Preferably, spacing flanges 26 are l k inches in height, however, the height thereof may be varied as desired. Spacing flanges 26 are provided with diamond-shaped embossed center marks 43 along the transverse walls thereof to define conventional center spacing locations. Underlying support flange 24 is provided with an opening means for receiving a bolt or the like 25 to anchor the grating structure 11 to a support 17. The support flange 24 has a transverse axis of about l inch, however, it may be longer if desired.

The main panel 21 is provided with a plurality of regularly spaced, transversely staggered, longitudinally-parallelly aligned, substantially elliptically-shaped openings 22, which may be formed by extrusion, stamping, etc. The openings are relatively deep-drawn and terminate at lower edge portions 21a to define therebetween a continuous land portion (or rib areas) 21b which further increase the strength characteristics of the grating structure. Perforated traction nubs 23 are provided along the peripheral edges of land portions 21b and have generally inclined surfaces 230 generallyintersecting at an edge positioned above the main panel portion to further resist slippage.

FIG. 5 illustrates a further embodiment of the invention wherein a grating structure 30 is suitably anchored, as by bolt means 31, to a support structure 17. The main panel 30a of grating structure 30 is also provided with turned under support flanges 24b substantially similar to those previously described, however, without the bolt-retaining slot means therein. The main panel portion 30a is provided with a plurality of regularly spaced parallel rows 22a, 22b of openings 22, and the openings in each row are disposed in staggered relationship to the openings in an adjacent row. Each row is separated by a substantially continuous rib area 21b extending the length of the rows. Traction nubs 23 are provided on each of the rib areas between the rows of openings and are spaced from one another along a line that extends the distance of the spaced openings 22. The traction nubs 23 (which may have a frustoconical cross section and be perforated) are spaced a longitudinal distance x (as measured from the longitudinal center axis of one traction nub to the longitudinal centerline of a longitudinally adjacent traction nub) away from one another to define substantially straight-lines along which bends, cuts, etc. may be made in accordance with a particular design. The cuts or bends made along the lines defined by the traction nubs 23 are smooth and nonjagged and do not require end-caps or the like. Preferably, the distance x is approximately l hinches, however, other distances may also be utilized. The longitudinal distance between any two longitudinally adjacent traction nubs is also substantially equal to the distance between the longitudinal center axis of any two adjacent parallel openings. The perforated traction nubs 23 are spaced a transverse distance d (as measured from the transverse center axis of one traction nub to the center axis of the transverse center of a transversely adjacent traction nub) away from one from one another substantially equal to the distance between the transverse center axis of one opening to an adjacently staggered (parallelly disposed) opening. The distance d is preferably l inches, however, other distances may also be utilized. Thus, the transverse spacing of traction nubs is substantially equal to the transverse spacing of openings and the longitudinal spacing of traction nubs is substantially equal to the longitudinal spacing of openings but the longitudinal spacing is different from the transverse spacing of said openings and nubs. Nevertheless, the spacing of the traction nubs and the openings is regular. The main panel portion of the grating structure 30 may also be provided with diamond shaped embossed center marks along its transverse edges to define more or less conventional center spacing locations, i.e., 6 inches, (substantially as discussed in conjunction with FIG. 4).

Referring now to the details of the openings 22, it will b noted they are substantially elliptically-shaped having a longitudinal axis 1 substantially greater than their transverse axis w. Preferably, the length 1 of the elliptically-shaped openings is l inches and the width w is three-fourths inch, however, if desired, other substantially proportionate dimensions may be utilized. The longitudinal margins of the openings thus provide greater curved areas along the peripheral edges of the rib areas between a pair of parallelly disposed openings adding further reinforcement to the rib areas. The openings 22 are substantially longitudinally parallelly aligned having a distance Z therebetween. In addition, the parallel rows of openings 22 are regularly spaced and alternatingly transversely staggered so that the transverse centerline of one row of openings substantially intersects and equally divides the distance 1 between two longitudinally-parallel openings in the adjacent row. The distance 2 may be one-quarter inch, however, this dimension may also be varied.

The longitudinally parallel rows of elliptically-shaped openings 22 are transversely spaced a distance y which is approximately equal to twice the distance that the parallelly disposed openings are transversely spaced from one another. Thus, distance y may be one-halfinch, however, it may be proportionately varied in regard to various other distances. It will thus be noted that the ribs defined between the parallelly disposed openings have'a land area with a transverse axis substantially equal to the distance y and, in view of the deepdrawn curvature of the openings 22 have a reinforced structure materially aiding the load bearing characteristics of the panel. Further, the openings 22 materially reduce the overall weight of the grating structure 30 and in combination with the ribs provide a relatively high strength to weight ratio. The

grating 30 is suitably anchored, as by bolt means 31, to anunderlying support structure 17 by means of a dish-shaped clamp member 34 which'nests within an elliptically-shapcd opening 22 retaining the bolt means 31 or the like thereat, as will be explained in further detail in conjunction with FIG. 6.

FIG. 6 illustrates an elevational view, of a portion of the grating structure 30 discussed in conjunction with FIG. -5. The

grating structure 30 is provided with a main panel portion 30a having its opposed longitudinal margin turned under to define spacing flanges 26 and. support flanges 24b. Support flanges 24b rest upon a support surface 17 which may be another structural element. The main body portion 30a is provided with a plurality of regularly spaced transversely staggered longitudinally-parallel substantially elIipticaIly-shaped openings 22 and a plurality of perforated traction nubs 23 substantially parallelly spaced apart from said openings 22. Certain edge openings 22 may be provided with dish-shaped clamp means 34 which nest within the openings 22.

As shown in FIG. 7, the dish-shaped clamp means 34 have a plurality of inwardly sloping angular sidewalls 38 defining substantially elliptically-shaped peripheral edges 41 and having a substantially flat centroidal portion 39 joining said sidewalls and defining a frustoconical cross section therewith. The clamp means 34 is provided with a centralized opening 42 in its flat centroidal portion 39 for receiving an anchoring means 31. The anchoring means 31, such as a bolt, has an upper portion 31a that is larger than the anchor receiving opening 42 in the clamp member 34 and thus is retainedby the flat surface portion of the clamp means. It will. be noted that the upper portions of bolt 31 is below the surface plane of the main panel portion 30a. Preferably, the sidewalls of the dish-shaped clamp member 34 extend a sufficient downward distance to accommodate the maximum-thickness of the upper portion of a fastener means so that no portion of the fastener means extends above the upper peripheral edges of the clamp member.

As shown shown in FIG. 7, the clamp member 34 has sidewalls 38 that substantially inwardly slop at an angle toward the centroidal flat portion 39, which joins the sidewalls .to define a dish-shaped body having outer peripheral edges 41. The edges 41 are substantially ellipticall y-shaped and are of such dimension as to substantially mate in a load bearing relationship with the openings 22 of the grating structure of the invention. The clamp member 34 merely nests within openings 22 and provides sufficient support around anchoring receiving opening for anchoring means to be passed therethrough and to hold the grating structure to another structural element.

Referring now to FIG. 10 wherein reference numeral 100 generally indicates a staircase construction utilizing the grid structure 11 of the invention in a more preferred embodiment. The staircase 100 is provided with upright end support members 12 and 13 and a centralized upright support member 14 suitably fastened by cleat means C to a base and provides a means of access from-a platform P to such a base. A stringer member .15 is suitably attached, as by bolt means 15a, 15b,

15 to support means 12, 13 and 14 in angular relationship to define the pitch of the stairs. A handrail member 16 is suitably attached, as by bolt means 19, 19a, 19b in a capping relationship with support means 12, 13 and 14 in a substantially parallel relationship to stringer member 15 to provide hand support for one using the stairs. As will be appreciated, substantially similar support means, stringer member and handrail member are also provided on the opposite side of the stair structure shown. a

As will be noted, stringermember 15 has a plurality of tread support members 17a suitably attached thereto, as by bolting, supporting individual stair treads 11. The arrangement of the stair support members 17 allows for relatively easy and fast installation along a stringer member while providing adequate support surfaces for a grid structure of the invention.

FIG. 11 illustrates further details of the connection between the stringer member 15 and a tread support, member 17a.

Stringer member 15 is composed of two Leshaped elements each having perpendicularly disposed flanges 15a, 15b and 15a and 15b. The construction in this position of these L- shaped elements is substantially similar to that described in conjunction with FIG. 2. The tread support member 17a has a support flange 17b and a main body portion 17b. The support flange 17b is provided with openings 170 to receive retaining means, such as bolts, for anchoring grating structures thereon. The main body portion 17b is provided with suitable openings receiving main support bolt members l7e and in addition provided with a plurality of variously disposed openings 17f allowing further adjustment of the tread support member 17a along stringer member. 15 to obtain the correct relationship therebetween allowing proper stair tread disposition. In other words, the openings l7e, 17 f in the support member 17a allow orientation thereof with openings 150, etc. to provide simple means of adjusting the level of the stair tread. It will also be noted that the support member 17a is adapted to support the stair tread above the stringer member 15. This method of construction allows the simple and fast installation of the tread support members along a stringer member.

FIG. 12 illustrates an exploded view of the portion of the handrail member 16a having a safety end cap 10a. The handrail 16a is constructed substantially as indicated in conjunction with FIG. 2 and is provided with an end cap having a main body portion 10a abutting against handrail 16a and an upper flange member 10d overlaying flange 16a of handrail 16. Main portion 10a of end cap 10a is also provided with side flanges 10c overlaying sidewalls 16b and 16b respectively of the handrail 16. Suitable retaining means, such as bolts 10b are provided for fastening the end cap to the handrail through appropriate openings 10c and 10d in the end cap which mate with openings in the handrail. This type of end cap provides an additional safety feature in the construction of a handrail in accordance with the invention.

To further illustrate the greatly improved load bearing capabilities of the grating structure of the invention, the following loading data is given for various typical 13 gauge (0.093 inch) grating structures having various spans between supports and showing the maximum deflection at the various loads ind cated.

.TAB LE I Concentrated Uniform Load in Span lbs. per between Load Deflection Load Deflection, square supports in lbs. inch in lbs. inch I001;

As will be appreciatedpa plurality of grating structures of the invention may be aligned in adjoining relationship to define catwalk areas, floor decking, etc.

ln summation, it will be seen that the invention provides a novel grating structure having improved load bearing characteristics and substantially higher strength to weight ratios which are extremely safe and provide sure footing and do not require any special nosing or end caps. The unique deepdrawn elliptically-shaped openings provide reinforced ribs therebetween materially aiding the structural strength of the grating structure thereby permitting fewer structural supports underneath reducing the total material required. Further, the grating structure has extreme versatility and may be utilized in a number of applications. The invention also provides a unique clamp member which may be utilized in conjunction with the grating structure of the invention to afford a novel means of anchoring the grating structure to other structural supports. The invention thus has attained each and every one of its objects, features and advantages. The grating structure of the invention is economical to manufacture and easily installed where desired.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

Iclaim:

1. A grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portion so as to define a channeled cross section, said panel having a plurality of regularly spaced transversely extending substantially elliptically-shaped openings having substantially uninterrupted ribs therebetween, said ribs each defining a centerline for cutting and bending without producing jagged peripheral edges along the margins of said panel, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said panel portion to resist slippage.

2. The grating structure as defined in claim 1 wherein the support flanges are provided with slots at the respective ends thereof for anchoring the grating structure.

3. A grating structure comprising a panel having a plurality of parallel rows of openings, the openings in each row being disposed in staggered relationship with the openings in the adjacent rows, each row being separated by a substantially continuous rib area extending substantially the length of the rows, said rib area defining a centerline for cutting and bending said panel without producing jagged peripheral edges along margins of said panel, and traction nubs provided on each of the rib areas between the rows extending along the length of said rows, said panel having means along its longitudinal margins for fastening the panel to other structural elements.

4. The grating structure as defined in claim 3 wherein a plurality of the panels are aligned in adjoining relationship to define a catwalk area.

5. The grating structure as defined in claim 3 wherein adjacently staggered openings have transverse center axis spaced apart a distance substantially equal to the distance between the transverse center axis of transversely adjacent traction nubs.

6. The grating structure as defined in claim 3 wherein the adjacent parallel openings have longitudinal center axis spaced apart a distance substantially equal to the distance between the longitudinal center axis of longitudinally adjacent traction nubs.

7. A grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions so as to define a channeled cross section, said panel having a plurality of regularly transversely staggered longitudinally-parallel substantially elliptically-shaped openings having substantially uninterrupted ribs therebetween extending a distance along said panel, said ribs each defining a centerline for cutting and bending without producing jagged peripheral edges along the margins of said panel, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs extending a distance substantially equal to the aforesaid distance, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage, and means for securing the sheet metal panel in assembly with another article comprising a dish-shaped clamp member having a plurality of inwardly sloping angular sidewalls defining uninterrupted elliptically-shaped peripheral edges for mating in a load bearing relation with the peripheral edges of said elliptically-shaped openings, and a substantially flat centroidal portion joining said sidewalls and generally defining a frustoconical cross section therewith, said flat centroidal portion having means defining a fastener-receiving opening, said dish-shaped clamp member nesting within an elliptically-shaped opening in the sheet metal panel.

8. The combination as defined in claim 7 wherein the inwardly sloping angular sidewalls of the dish-shaped clamp member extend a downward distance sufficiently greater than the thickness of the upper portion of a fastener means whereby no portion of the fastener means extends above the upper peripheral edges of said clamp member.

9. In combination, a plurality of upright support members parallelly spaced apart a distance, said upright support members being of decreasing length, a handrail member attached to the upper portion of each of said upright support members, a pair of stringer members substantially parallelly spaced from said handrail and attached to said upright support members at a point below said handrail, a plurality of tread support members parallelly attached to said stringer members extending transversely thereof, and a plurality of tread structures attached to said tread support members in substantially parallel relationship therewith, a tread structure comprising a grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions defining a channeled cross section, said panel having a plurality of regularly transversely staggered longitudinally-parallel substantially elliptically-shaped openings defining substantially uninterrupted ribs therebetween, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage on the tread structure, said support flange being directly fastened to a tread support member.

10. The combination as defined in claim 9 wherein the tread support members are disposed along the stringer members to support the tread structure above said stringer members.

11. The combination as defined in claim 9 wherein the tread structure members are disposed along the stringer member to support the tread structure below said stringer member.

12. The combination as defined in claim 9 wherein the handrail member is provided with an end cap member in capping relationship with the longitudinal edges thereof.

13. A clamp member for securing grating members having elliptical openings therein to structured elements comprising, an elliptical dish-shaped body having a plurality of inwardly sloping angular sidewalls defining uninterrupted ellipticallyshaped peripheral edges for contact with the peripheral edges of the elliptical openings of said grating member and a substantially flat centroidal portion joining said sidewall and defining a substantially frustoconical cross section therewith, said flat centroidal portion having means defining a fastenerreceiving opening, said dish-shaped body nesting within the elliptical openings of the grating member, said sloping angular sidewalls extending a downward distance substantially greater than the thickness of the upper portion of a fastener means whereby no portion of the fastener means extends above the upper peripheral edges of said clamp member.

14. In combination, a pair of L-shaped structural members,

each of said members having perpendicularly disposed flanges, one of said flanges being wider than the other, the

st i g ws ahs sqb em y B a of regularly disposed openings in adjustable registry with at least some of the openings of said wider flanges for receiving a fastening means therethrough, said elongated margin of the support member being adapted to support a grating structure and anchoring means fastening the support member to the overlapping L-shaped structural members by passing through the openings of said members in registry with one another.

15. The combination as defined in claim 14 wherein the ,elongated margin of the triangularly shaped support member is provided with openings along the longitudinal margins thereof.

16. In combination, a plurality of upright support members I parallelly spaced apart a distance; said upright support members being of decreasing length, a handrail member attached to the upper portion of each of said upright members, a pair of handrail and attached to each of said upright members, said stringer members having a plurality of openings therein, a plurality of tread support members attached to said stringer members in substantially parallel relationship therewith, each of said tread support members having a plurality of openings in substantial registry with at least some of the openings in said stringer members, anchoring means passing through said openings joining said tread support members with said stringer members in an adjustable relationship, a tread structure comprising a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions defining a channeled cross section, said main panel having a plurality of regularly transversely staggered longitudinally-parallel substantially ellipticallyshaped openings defining substantially uninterrupted longitudinally extending rib areas therebetween extending a distance along said main panel, and a plurality of frustoconical perforated traction nubs carried by said main panel in substantial alignment with each other and said rib areas extending a distance substantially equal to the aforesaid distance, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage on said tread structure, said support flanges being leuy Spaced below Said directly fastened to opposing tread support members. 

1. A grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portion so as to define a channeled cross section, said panel having a plurality of regularly spaced transversely extending substantially elliptically-shaped openings having substantially uninterrupted ribs therebetween, said ribs each defining a centerline for cutting and bending without producing jagged peripheral edges along the margins of said panel, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said panel portion to resist slippage.
 2. The grating structure as defined in claim 1 wherein the support flanges are provided with slots at the respective ends thereof for anchoring the grating structure.
 3. A grating structure comprising a panel having a plurality of parallel rows of openings, the openings in each row being disposed in staggered relationship with the openings in the adjacent rows, each row being separated by a substantially continuous rib area extending substantially the length of the rows, said rib area defining a centerline for cutting and bending said panel without producing jagged peripheral edges along margins of said panel, and traction nubs provided on each of the rib areas between the rows extending along the length of said rows, said panel having means along its longitudinal margins for fastening the panel to other structural elements.
 4. The grating structure as defined in claim 3 wherein a plurality of the panels are aligned in adjoining relationship to define a catwalk area.
 5. The grating structure as defined in claim 3 wherein adjacently staggered openings have transverse center axis spaced apart a distance substantially equal to the distance between the transverse center axis of transversely adjacent traction nubs.
 6. The grating structure as defined in claim 3 wherein the adjacent parallel openings have longitudinal center axis spaced apart a distance substantially equal to the distance between the longitudinal center axis of longitudinally adjacent traction nubs.
 7. A grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions so as to define a channeled cross section, said panel having a plurality of regularly transversely staggered longitudinally-parallel substantially elliptically-shaped openings having substantially uninterrupted ribs therebetween extending a distance along said panel, said ribs each defining a centerline for cutting and bending without producing jagged peripheral edges along the margins of said panel, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs extending a distance substantially equal to the aforesaid distance, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage, and means for securing the sheet metal panel in assembly with another article comprising a dish-shaped clamp member having a plurality of inwardly sloping angular sidewalls defining uninterrupted elliptically-shaped peripheral edges for mating in a load bearing relation with the peripheral edges of said elliptically-shaped openings, and a substantially flat centroidal portion joining said sidewalls and generally defining a frustoconical cross section therewith, said flat centroidal portion having means defining a fastener-receiving opening, said dish-shaped clamp member nesting within an elliptically-shaped opening in the sheet metal panel.
 8. The combination as defined in claim 7 wherein the inwardly sloping angular sidewalls of the dish-shaped clamp member extend a downward distance sufficiently greater than the thickness of the upper portion of a fastener means whereby no portion of the fastener means extends above the upper peripheral edges of said clamp member.
 9. In combination, a plurality of upright support members parallelly spaced apart a distance, said upright support members being of decreasing length, a handrail member attached to the upper portion of each of said upright support members, a pair of stringer members substantially parallelly spaced from said handrail and attached to said upright support members at a point below said handrail, a plurality of tread support members parallelly attached to said stringer members extending transversely thereof, and a plurality of tread structures attached to said tread support members in substantially parallel relationship therewith, a tread structure comprising a grating structure comprising a one-piece sheet metal panel having a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions defining a channeled cross section, said panel having a plurality of regularly transversely staggered longitudinally-parallel substantially elliptically-shaped openings defining substantially uninterrupted ribs therebetween, and frustoconical perforated traction nubs carried by said panel in substantial alignment with said ribs, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage on the tread structure, said support flange being directly fastened to a tread support member.
 10. The combination as defined in claim 9 wherein the tread support members are disposed along the stringer members to support the tread structure above said stringer members.
 11. The combination as defined in claim 9 wherein the tread structure members are disposed along the stringer member to support the tread structure below said stringer member.
 12. The combination as defined in claim 9 wherein the handrail member is provided with an end cap member in capping relationship with the longitudinal edges thereof.
 13. A clamp member for securing grating members having elliptical openings therein to structured elements comprising, an elliptical dish-shaped body having a plurality of inwardly sloping angular sidewalls defining uninterrupted elliptically-shaped peripheral edges for contact with the peripheral edges of the elliptical openings of said grating member and a substantially flat centroidal portion joining said sidewall and defining a substantially frustoconical cross section therewith, said flat centroidal portion having means defining a fastener-receiving opening, said dish-shaped body nesting within the elliptical openings of the grating member, said sloping angular sidewalls extending a downward distance substantially greater than the thickness of the upper portion of a fastener means whereby no portion of the fastener means extends above the upper peripheral edges of said clamp member.
 14. In combination, a pair of L-shaped structural members, each of said members having perpendicularly disposed flanges, one of said flanges being wider than the other, the wider flanges being positioned in overlapping contiguous surface contact with each other to define a channel cross section therebetween, said wider flanges having a plurality of regularly disposed parallel openings positioned a distance away from the transverse edges thereof, a substantially triangularly shaped support member having a main body portion with an elongated margin thereof substantially perpendicular to said main body portion, said main body portion having a plurality of regularly disposed openings in adjustable registry with at least some of the openings of said wider flanges for receiving a fastening means therethrough, said elongated margin oF the support member being adapted to support a grating structure and anchoring means fastening the support member to the overlapping L-shaped structural members by passing through the openings of said members in registry with one another.
 15. The combination as defined in claim 14 wherein the elongated margin of the triangularly shaped support member is provided with openings along the longitudinal margins thereof.
 16. In combination, a plurality of upright support members parallelly spaced apart a distance, said upright support members being of decreasing length, a handrail member attached to the upper portion of each of said upright members, a pair of stringer members substantially parallelly spaced below said handrail and attached to each of said upright members, said stringer members having a plurality of openings therein, a plurality of tread support members attached to said stringer members in substantially parallel relationship therewith, each of said tread support members having a plurality of openings in substantial registry with at least some of the openings in said stringer members, anchoring means passing through said openings joining said tread support members with said stringer members in an adjustable relationship, a tread structure comprising a main panel portion with its opposite longitudinal margins turned under and providing support flanges underlying the main panel portions defining a channeled cross section, said main panel having a plurality of regularly transversely staggered longitudinally-parallel substantially elliptically-shaped openings defining substantially uninterrupted longitudinally extending rib areas therebetween extending a distance along said main panel, and a plurality of frustoconical perforated traction nubs carried by said main panel in substantial alignment with each other and said rib areas extending a distance substantially equal to the aforesaid distance, said frustoconical traction nubs having inclined surfaces intersecting at an edge positioned above said main panel portion to resist slippage on said tread structure, said support flanges being directly fastened to opposing tread support members. 